JPS6153752A - Lead frame - Google Patents

Abstract

PURPOSE:To obtain a small size high power semiconductor device by integrally providing a wire heat radiation fin between tab and tab suspending lead. CONSTITUTION:The lead positioning holes 2 are provided with a constant interval to the external frame 1 and the pellet setting tab 5 integrally having a heat radiation fin is provided through a tab suspending lead. Thereby, a couple of pins can be provided more than the case where the tab suspending lead is independently provided in this frame. This fin 4 is branched to three portions by a resin filling hole 6 at the area near the mold line. The one becomes the tab suspending lead, and the other two is in the same shape as the outer lead at the outside of dam tie-bar 7. A pair of fins 4 are provided with dam tie-bar 7 in such a way as surrounding the tab 5 with a constant interval and this tie-bar 7 is provided with may inner lead 8 and outer leads 9. Moreover, the base portion of fin 4 is sufficiently wider than the lead 8 and it becomes wider toward the base, showing excellent heat radiation and heat conduction property.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field] The present invention relates to a technique that is particularly effective when applied to lead frames of semiconductor devices.

[Background technology]

Published by Nippon Varnish, Varnish, Tee Co., Ltd., [5olidSt
ate technology/Japan Edition J, 1982 Japan Edition, pages 69 to 77, semiconductor devices, in particular, multi-functionalization of each IC package.

Miniaturization is progressing. Among these, the emergence of a power IC equipped with a high output circuit for driving a motor, for example, is desired.

However, by providing a high output circuit, the heat generated due to the large circuit loss inhibits the operation of other circuits. For this reason, it is necessary to dissipate that heat outside the package, and conventionally, a heat sink equivalent to a radiation fin was used to dissipate the heat outside the package.
Each package was provided independently and separately. Therefore, it was found that the heat conduction efficiency from the tab on which the pellet was placed to the heat sink was poor, the thermal resistance of the package increased, and it was difficult to obtain a high output type IC package. In addition, it was inevitable that the structure would be larger and the price would be higher.

[Purpose of the invention]

The purpose of the present invention is to improve the thermal conductivity from the tab to the radiation fins by integrating the radiation fins into the tab on which the pellet is placed, and to achieve high output even though the IC package is small and has many bins. An object of the present invention is to provide a lead frame for a semiconductor device that embodies functions.

The above and other objects and novel features of the present invention include:
It will become clear from the description herein and the accompanying drawings.

[Summary of the invention]

A brief summary of typical inventions disclosed in Fufu 1 is as follows.

That is, in the present invention, by integrally connecting a wide heat dissipation fin between the tab and the tab suspension lead, the heat of the tab heated by the pellets is quickly absorbed by the heat dissipation fin, and the pellets on the tab are efficiently removed. Cooling. This results in
A high-power semiconductor device can be obtained in a small size and at low cost.

〔Example〕

FIG. 1 shows a partially cutaway view of an embodiment of the lead frame of the present invention. In this example, we will use a mini-software
This figure shows a lead frame for a package. Although only a pair of lead frames are shown in the figure, they are formed continuously over a length of, for example, seven packages. Lead positioning holes 2 are provided in this lead frame outer frame 1 at regular intervals. Further, a pellet and a mounting tab 5 integrally having heat dissipating fins 4 are connected to the pair of lead frame outer frames 1 via tab hanging leads 3. Therefore, this frame allows for two more pins than when tab suspension leads are provided independently. In the same figure, the dotted line indicates the corner and mold line. The heat dissipation fin 4 is divided into three parts near the mold line by resin filling holes 6. One is a tab suspension lead, and the other two are thicker than the outer lead 9 inside the dam tie bar 7 and have the same shape as the outer lead outside the dam tie bar 7. The reason for this is due to considerations such as ease of mounting onto a printed circuit board and heat dissipation, as will be described later.

Furthermore, a dam tie bar 7 is connected to the pair of radiation fins 4 so as to surround the tab 5 at a certain distance.
A large number of inner leads 8 and outer leads 9 are arranged in series. Furthermore, the base of the heat dissipation fin 40 is sufficiently wider than the inner lead 8, and widens at the end to improve heat dissipation.
Efficiency, thermal conductivity.

It has become

In addition, at the 8 ends of each inner lead, there is a mark A on the pad part of the pellet.
U-wire etc. are wire-pounded. 10 is a positioning hole for the tab 5 of the pellet.

With such a lead frame shape, heat generated when the pellet is configured as a high-power IC can be transferred to the radiation fins 4 through the tabs 5, and the portion of the radiation fins 4 exposed from the resin package body is exposed to the outside air and cooled by air. Alternatively, the heat radiation fins 4 can be brought into contact with another heat sink for indirect cooling.

Further, a pellet is placed on the tab 5, and after the wire pounding is performed, the lead frame is held between the upper mold and the lower mold, and resin is injected at 20 to 100 Kl/=-1. After curing, the dam tie bars 7 and tab leads 3 are cut off as desired to obtain a semiconductor device package as shown in FIGS. 2 and 2b.

The second figure shows the state mounted on a printed circuit board 20 (wiring not shown).

What should be noted in the figure is that the pancage shape and the arrangement of the outer leads 9 and the first part 9' of the heat dissipation fins are the same as those of the mini sphere package, or are only slightly different in the three tab suspension leads. . That is, the production and mounting equipment for mini software packages can be used as is. The aforementioned lead frame is also used for mini-square packages, and since the parts other than the frame and the radiation fins are left blank, the equipment and wire bonder can be used in common for the lead frame with pellets.

If there is no through hole 6 for resin filling, the area of the heat dissipation fin 4 is small, and the binding strength of the upper and lower resins in this area is poor.
Vulnerable to water intrusion. In this embodiment, by providing a through hole 6 and filling the through hole 6 with resin, the adhesion between the heat dissipating fin 4 and the resin is improved and water is prevented from entering.

Furthermore, when cutting off the dam tie bar 7 or the tab suspension lead 3, the outer lead 9 can be
It can prevent the tip of the tab suspension lead 3 from protruding from the tip, and when it is mounted on a printed circuit board, it can be mounted in the hole 21 formed in the same pattern as the electrode pattern of a normal mini sphere package. . That is, it becomes possible to standardize the electrode pattern, and the design of the printed circuit board becomes easier.

As described above, in the semiconductor package having the lead frame of the present invention, the frame material is made of copper-based metal with a thickness of 0.25 m.
Even when using a board of m, the power consumption (Pd) is approximately 1
．． Operation at 5W to 2W is now possible. In addition, the tab suspension lead 3 constitutes a part of the heat dissipation part together with the heat dissipation fin,
Make effective use of the tab suspension lead 3.

〔effect〕

fil The present invention has a structure in which the outer frame of the lead frame and the tab are connected by a heat radiation fin through a tab suspension lead, thereby making it possible to have multiple bins and directly transmitting the heat generated by the pellet to the heat radiation fin with low thermal resistance. This heat can be further dissipated to the outside air through the tab suspension lead exposed to the outside of the package. Therefore, the heat dissipation of the pellet becomes more efficient, and it becomes possible to manufacture a small semiconductor device with large power consumption.

+21 In the present invention, by making the unit area of the radiation fins sufficiently larger than that of the inner lead, the heat of the tab can be quickly absorbed into the radiation fins, and the heat radiation efficiency of the above-mentioned Il+ pellet can be dramatically increased. can.

(3) The present invention improves the adhesion of the resin (mold material) to the heat dissipation fins by providing resin-filling holes in the heat dissipation fins, thereby preventing water from entering the package.
Mechanical damage can be effectively prevented.

Hereinafter, the invention made by the present inventor has been specifically explained based on examples, but the present invention is not limited to the above-mentioned examples, and it is understood that various changes can be made without departing from the gist of the invention. Needless to say.

[Application field]

In the following explanation, we will mainly explain the invention made by the present inventor in terms of the application field for which it was made, which is mini-software.
Although the case where the present invention is applied to packaging technology has been described, the present invention is not limited thereto, and can be applied to other packages such as dual in-line packages.

[Brief explanation of the drawing]

FIG. 1 is a partially cutaway plan view showing an embodiment of the lead frame of the present invention, and FIGS. 20 and 2b are perspective views of a semiconductor pancage. ]...Lead frame outer frame, 3...Tab suspension lead, 4...Cooling fin, 5...Tab, 6...Through hole for resin filling, 7...Dam tieper, 8...Inner Lead, 9...outer lead.

Claims (1)

[Claims] 1. A lead frame in which a pellet mounting tab is supported by a tab suspension lead on a pair of lead frame outer frames, and cooling fins are provided in series between the tab suspension lead and the tab.